AN EXPERIMENTAL INVESTIGATION OF WALL EFFECTS ON SUPERCAVITATING HYDROFOILS OF FINITE SPAN

A geometrically similar family of three supercavitating hydrofoils was tested in the M.I.T. variable pressure water tunnel. The half-span foils were of elliptical planform; the ratio of foil half-span to tunnel height was 1/4 for the small foil, 1/2 for the medium foil, and 3/4 for the largest foil. The tunnel was of square cross section. Lift, drag, moment, tunnel speed, ambient pressure, and cavity pressure were measured for attack angles from 8 to 21 degrees and a variety of ambient pressure settings; cavity length measurements were obtained from photographs. Results were compared with theoretical results obtained by Leehey, and also with a more detailed numerical lifting surface procedure developed by Jiang and Leehey. For the small and medium foils, it was sufficient to correct only for the effect on downwash of the images of the trailing vortices. The large foil data, however, required further correction; upon application of the same corrections which were applied to the data for the two smaller foils, the force and moment data for the large foil plotted slightly lower than did the data for the two smaller foils, while the cavity length data for the large foil indicated cavity lengths significantly larger than for either of the theoretical predictions or the cavity length data for the two smaller foils. Through the application of existing two-dimensional corrections, the force data for the large foil were brought into close agreement with the force data for the two smaller foils, but no suitable correction factors exist for the cavity length data.

  • Supplemental Notes:
    • Also available from NTIS, AD-A045769/7ST.
  • Corporate Authors:

    Massachusetts Institute of Technology

    Department of Ocean Engineering, 77 Massachusetts Avenue
    Cambridge, MA  USA  02139
  • Authors:
    • Maixner, M R
  • Publication Date: 1977-9

Subject/Index Terms

Filing Info

  • Accession Number: 00165283
  • Record Type: Publication
  • Source Agency: Massachusetts Institute of Technology
  • Report/Paper Numbers: Ms Thesis
  • Files: TRIS
  • Created Date: Nov 23 1977 12:00AM